Population=[[400;120],zeros(2,30)];
for i=1:30
	if(rand(1)<0.35)
		Population(1,i+1)=Population(1,i)*0.9;
		else
			Population(1,i+1)=Population(1,i)*1.1;
	end;
	if(rand(1)<0.35)
		Population(2,i+1)=Population(2,i)*0.8;
		else
			Population(2,i+1)=Population(2,i)*1.2;
		end;
end;

figure;
hold on;
plot(0:30,Population(1,:),'r');
plot(0:30,Population(2,:),'g');
xlabel('Day');
ylabel('Number');
GLegend=legend('Me','Assistant');
set(GLegend,'Location','NorthWest');